LXXIX. ALISMACER. 4.29 
LXXIX. ALISMACEA. THE ALISMA FAMILY. 
Marsh or water plants, with radical leaves and _ leafless 
flower-stems (except in Scheuchzeria). Flowers in terminal 
umbels, panicles, or racemes. Perianth of 6 segments, either 
all similar, or 3 outer small and sepal-like and 3 inner ones 
larger and petal-like. Stamens 6, 9, or indefinite. Ovary of 
3, 6, or many carpels, either distinct from the first or separable 
when in ripe fruit, each with 1, 2 or many ovules. Seeds 
consisting, within the testa, of a homogeneous mass, usually 
considered as an undivided embyro without albumen. 
The genera are not numerous, but several of them are dispersed over 
the greater part of the world.. 
Perianth-segments all nearly equal, large and coloured. 
Flower-stem tall, with a large terminalumbel . A - 1, Buromtvs. 
Perianth-segments 3 small and herbaceous, 3 large and 
coloured. Flowers opposite or whorled, in a terminal 
raceme, umbel, or panicle. 
Carpels and stamens numerous. Leaves sagittate. p . 2, SAGITTARIA, 
Carpels numerous. Stamens 6. Leaves ovate or narrow . 3. ALISMA. 
Carpels 6. Stamens 6. Leaves ovate or oblong . - 4. DAMASONIUM. 
Perianth-segments all small and slightly coloured. Flowers 
alternate, in a raceme or spike. 
Carpels 3, distinct. Stem leafy, rush-like — , 5. ScHEUCHZERIA, 
Carpels 3, united till they ripen. Leaves linear, all radical . 6. TRIGLOCHIN. 
I. BUTOMUS. BUTOME. 
A single species, distinguished from Alisma as a genus, or by some bota- 
nists as an independent family, chiefly on account of the ovary, which has 
several ovules in each carpel. 
1, B. umbellatus, Linn. (fig. 967). Common Butome, Flowering 
Rush.— A perennial, with a thick, creeping rootstock, and ‘long, erect, 
sedge-like triangular radical leaves, broad and sheathing at the base. 
Flower-stem leafless, 2 to 4 feet high, thick and rush-like, bearing a large 
umbel of showy, rose-coloured flowers, with 3 lanceolate, thin bracts at 
its base. Pedicels 3 to 4 inches long, often 20 to 30 in the umbel. 
Perianth fully an inch diameter, of 6 ovate, spreading, nearly equal seg- 
ments. Stamens 9. Carpels 6, erect, tapering into short styles, seeds 
numerous minute. . 
In watery ditches, and still waters, over Europe and temperate Asia, 
except the extreme north. Central and southern England, rare in Ireland, 
introduced only in northern England and Scotland. Fl. summer. 
Il. SAGITTARIA. ARROWHEAD. 
Aquatic herbs, differing from Alisma in their unisexual flowers, the 
males with numerous stamens, the females with very numerous ‘small 
carpels in a dense head, 
Besides the common species, there are several from North and South 
America, and eastern Asia. 
1. Sagittaria sagittifolia, Linn. (fig. 968). Common Arrowhead. 
—A perennial, with a creeping rootstock, forming bulb-like tubers. Leaves 
radical, rising out of the water on very long stalks; the blade 6 to 8 inches 
